The Dragon 2 will be able to dock with the ISS and other space habitats automatically without needing the intervention of a robotic arm. It will run on a SuperDraco engine—a thruster made by SpaceX and the first engine ever built completely by a 3-D printer to go into space. This means that a machine guided by a computer formed the engine out of single piece of metal—in this case the high-strength alloy Inconel—so that its strength and performance should exceed anything built by humans by welding various parts together. And
